Electric drive unit consisting of an electromotor and an electronic module

ABSTRACT

An electric drive unit provides a simple and economical electrical connection of an electric motor and an electronic module. The commutator of the electric motor, a brush rocker ring arranged on the commutator, and the drive shaft of the electric motor as well as the carrier body of the electronic module are inserted into a transmission housing. In the transmission housing, the carrier body of the electronic module is positioned so that contact elements provided on the brush rocker ring engage into contact points provided on the carrier body of the electronic module. The electric drive unit can be used for window lifter drives.

BACKGROUND INFORMATION

Electric drive units are used in diverse application fields; for examplein the motor vehicle field, various movable parts of the motor vehicle(seats, window lifters, sliding sunroofs, etc.,) are operated by meansof electric drive units. Electric drive units consist of an electromotor(i.e. electric motor) (for example a direct current motor) forgenerating and providing electrical drive power, and of an electronicmodule for controlling/driving and monitoring the electric motor (forexample for the rotational speed and power regulation of the electricmotor), as well as for the realization of additional functions, as thecase may be. For carrying out the movement of the drive shaft of theelectric motor, there is provided a transmission arranged in atransmission housing, and the electric motor is connected in a suitablemanner with the transmission. An electrical connection is requiredbetween the electronic module and the electric motor for furtherconveying sensor signals and control signals, as well as for the voltagesupply. In connection with a direct current motor as the electric motor,for this purpose, the collector or commutator of the electric motor isconnected with the electronic module, which is arranged on a carrierbody (for example a circuit board). Typically, the electrical connectionis realized via connection lines embodied as a cable, which connectionlines are connected by means of connector plugs to the plug connectionson the electronic module housing and the electric motor housing.

In this context it is disadvantageous that this connection betweenelectric motor and electronic module is complicated and costly, andgives rise to problems with respect to reliability, aging, etc., andnecessitates a high surface area requirement, so that the installationvolume of the electric drive unit is large and the production of theelectric drive unit is connected with relatively high costs.

SUMMARY OF THE INVENTION

The object underlying the invention is to propose an electric drive unitthat comprises advantageous characteristics in comparison to the above,especially a simple construction and low costs, a high reliability, anda simplified manufacturing.

This object is achieved according to the invention electric drive unitcomprising an electric motor, an electronic module, and a transmission,wherein a commutator, a brush rocker ring arranged on and extendingcircumferentially around the commutator, and a drive shaft of theelectric motor, as well as a carrier body of the electronic module areinserted into a transmission housing and wherein an electricalconnection between the electric motor and the electronic module isachieved in the transmission housing via contact elements which arefixedly arranged on the brush rocker ring and which releasably engageinto contact points fixedly provided on the carrier body of theelectronic module.

Electric motor and electronic module form a drive unit that isintegrated in or with the transmission housing, especially theelectrical connection between electric motor and electronic module isrealized in the transmission housing via contact elements (for examplepress-in contacts) arranged on the brush rocker or bridge, whereby thecontact elements engage into corresponding contact points on the carrierbody of the electronic module (for example into through-contacts of acircuit board). For contacting the electric motor, two contact elements(press-in contacts) are required on the commutator of the electricmotor, and therewith on the brush rocker, and consequently twocorresponding contact points are required on the carrier body; however,more contact elements (press-in contacts) may also be provided on thebrush rocker and therewith also more corresponding contact points can beprovided on the carrier body, whereby number and arrangement of thepress-in contacts on the brush rocker and therewith also number andarrangement of the corresponding contact points on the carrier body areselected dependent on the characteristics of the electric drive unit,especially dependent on the current requirement of the electric driveunit or the required current carrying capacity.

Recesses for the electric motor and the electronic module are providedin the transmission housing on its front side (end face side),especially, a first recess is provided for the drive shaft, thecommutator, and the brush rocker of the electric motor, and a secondrecess is provided for the connection part of the electronic modulecomprising connector plug contacts. Drive shaft, commutator, and brushrocker of the electric motor are inserted into the first recess in thetransmission housing in such a manner, so that the electric motorhousing which encloses the rotor (armature) of the electric motor liesflushly on the transmission housing. The electronic module is introducedinto the transmission housing from the upper side of the transmissionhousing, whereby the connector part of the electronic module is insertedinto the second recess in the transmission housing and the carrier bodyof the electronic module, with the aid of guides applied on the interiorwall of the transmission housing, is positioned in such a manner, sothat the carrier body is arranged parallel to the bottom side (to thebase surface or to the floor) of the transmission housing and therebyits upper surface normal vector or axis extends perpendicularly (at anangle of 90°) relative to the axis of the drive shaft of the electricmotor and the contact points on the carrier body of the electronicmodule come to rest on the contact elements (press-in contacts) arrangedon the brush rocker. By the application of pressure, for example bymeans of a press, the contact elements (press-in contacts) are connectedwith the contact points (for example the press-in contacts are pressedinto the through-contacts of a circuit board), whereby electric motorand electronic module are electrically connected with one another. Forprotection against environmental influences or for stability reasons, ahousing part (embodied as a lid of the transmission housing) can bearranged as the upper or top side of the transmission housing and herebya closed transmission housing can be realized. The securing of theelectric motor housing on the transmission housing, and therewith themechanical connection between electric motor and transmission(transmission housing) is achieved by means of suitable securingelements, for example via screws inserted into corresponding bored holesin the electric motor housing and transmission housing.

In the electronic module, there can be arranged several functional unitsarranged on the circuit carrier in a compact construction: for example apower unit with power semiconductor components, a control/driving unit,an anti-interference unit for suppressing the effects of the commutationprocesses of the electric motor (brush arcing) as well as the connectorpart with the connector plug contacts. Preferably the electronic modulecomprises at least one rotation speed sensor (for example a Hall sensor)for detecting the rotational speed of the electric motor, which sensorcan be positioned at (any desired) suitable place on the carrier body;especially the rotation speed sensor is positioned on the carrier bodyin such a manner so that a sufficient coupling is provided to atransmitter or emitter applied on the drive shaft of the electric motor,for example a sufficient magnetic coupling of a Hall sensor to anemitter magnet applied on the drive shaft of the electric motor. Thedimensioning of the carrier body (of the circuit board) is guided by thenumber of the components of the electronic module, and can be optimizedin accordance with the surface area required therefor.

Due to the realization of a very short internal electrical connectionbetween electric motor and electronic module, separate connection linesare omitted, and also the problems connected herewith (spacerequirement, reliability, costs, etc.); therefore, in the integration ofelectric motor and electronic module in a compact electric drive unit,only small installation volumes are necessary and good electricalcharacteristics, a high reliability and a high operating life areensured.

BRIEF DESCRIPTION OF THE DRAWINGS

In connection with the drawing (FIGS. 1 and 2) the electric drive unitshall be described in connection with an example embodiment.

FIG. 1 shows a three-dimensional view of the electric drive unit withthe individual components,

FIG. 2 shows a three-dimensional view of the electric drive unit withouttransmission housing.

DETAILED DESCRIPTION OF A PREFERRED EXAMPLE EMBODIMENT OF THE INVENTION

The electric drive unit of electric motor 10, electronic module 20 andtransmission 30 is, for example, integrated in a door control device ofa motor vehicle for realizing the electric window lifter function.

The electric motor 10 of the electric drive unit is a direct currentmotor with a nominal rated power of, for example, 200 W, whereby therotor 11 (the winding or the armature) of the electric motor 10 isenclosed by the electric motor housing 12. The electric motor 10possesses a collector or commutator 15 (commutator ring) located on theend face 13 and connected with the working shaft 14 (drive shaft), and abrush rocker 16 arranged on the commutator 15 for contacting thecommutator 15; the brush rocker 16 is embodied as a circumferential orencircling plastic ring and carries on its upper surface 17, contactelements 18 embodied as press-in contacts, for example four press-incontacts 18 are provided, of which respectively two press-in contactsare connected via an internal connecting line with the two connectionsof the electric motor 10. Furthermore, a ring magnet functioning as atransmitter or emitter magnet 19 is arranged on the drive shaft 14 ofthe electric motor 10.

The electronic module 20 of the electric drive unit is arranged on asuitable carrier body 21 (for example on a circuit board) and possesses,as functional units, for example, a power unit with power components 22for controlling/driving the electric motor 10, and an anti-interferenceunit with interference suppression components 23 (for examplecapacitors) for suppressing the effects of the switching processes(commutation processes or brush arcing) of the electric motor 10 and forpreventing external interfering influences such as EMC incidentradiation, current waviness (ripples) or over-voltage conditions, etc.On the circuit board 21 there is arranged a connector part 26 with aplurality of connector plug contacts 27, onto which external connectorplugs can be connected. Furthermore, a Hall sensor functioning as arotation speed sensor 24 is provided as a SMD component, which ispositioned on the circuit board 21 below the ring magnet 19 arranged onthe drive shaft 14 of the electric motor 10, and which is connected witha corresponding functional unit of the electronic module 20 forevaluation of the sensor signal of the rotation speed sensor 24. Thecomponents 22, 23 of the electronic module 20 are mounted on the circuitboard 21, for example, by soldering or as SMD components by means ofsurface mounting. Moreover, a number of contact points 25 correspondingto the number of the press-in contacts 18 on the brush rocker 16 areprovided on the circuit board 21, which contact points are, for example,embodied as through-contacts in the circuit board 21; for example forincreasing the current carrying capacity of the electrical connectionbetween electric motor 10 and electronic module 20 (for example in theoperation of the electric drive unit, currents up to 20 Amps can arise),four press-in contacts 18 are provided on the brush rocker 16 andconsequently also four through-contacts 25 are provided in the circuitboard 21 for receiving the press-in contacts 18 on the brush rocker 16.

Before the joining of electric motor 10 and electronic module 20, thedrive shaft 14 of the electric motor 10, with the ring magnet 19arranged thereon, as well as the commutator 15 of the electric motor 10with the brush rocker 16 and the press-in contacts 18, are inserted intoa first recess 32 on the front side 35 (end face side) of thetransmission housing 31, which is dimensioned in such a manner so thatthe electric motor housing 12 lies flushly on the front side 35 (endface side) of the transmission housing 31. For sealing the electricmotor 10 (electric motor housing 12) toward the transmission housing 31,a seal 40 is provided, which encompasses or surrounds the first recess32 on the front side 35 of the transmission housing 31 in connectionwith the insertion of the mentioned components of the electric motor 10into the transmission housing 31.

During the joining together of electric motor 10 and electronic module20, the electronic module 20 is inserted from the upper side 36 of thetransmission housing 31 into the transmission housing 31, whereby theconnector part 26 of the electronic module 20 arranged on the upper side29 of the circuit board 21 and contacted with the circuit board 21 isinserted in a form-fitting manner with the connector plug contacts 27into a second recess 33 on the front side 35 of the transmission housing31, and the circuit board 21 with the components 22, 23 arranged on itsupper surface 29 is inserted flushly into the transmission housing 31with the aid of guides applied on the inner side of the transmissionhousing 31; hereby the electronic module 20 is fixed in the transmissionhousing 31 and is positioned relative to the components of the electricmotor 10 that have already been introduced there—especially thethrough-contacts 25 of the circuit board 21 are guided over the press-incontacts 18 on the brush rocker 16, and the circuit board 21 with thecomponents 22, 23, 24 is positioned in a certain position relative tothe underside 38 (to the floor) of the transmission housing 31 andtherewith relative to the components of the electric motor 10 arrangedin the transmission housing 31. The electrical connection betweenelectric motor 10 and electronic module 20 is achieved by exertingpressure onto the underside 28 of the circuit board, and the herebynecessitated pressing-in of the press-in contacts 18 into thethrough-contacts 25 of the circuit board 21; this pressing-in operationis achieved, for example, by means of a bellcrank or toggle press. Themechanical fixing of the electric motor 10 and therewith also of theelectronic module 20 with the transmission 30 (the transmission housing31) is achieved by suitable securing means 41; for example by screws 41,which are guided through openings 42 on the electric motor housing 12and openings 43 on the seal 40, and which engage into bored holes 34 onthe front side 35 (end face side) on the transmission housing 31.

A housing part 37 functioning as a lid is placed onto the upper side 36of the transmission housing 31, so that a closed transmission housing31, which is protected against external environmental influences, isrealized. Connection lines or connector plugs can be externallyconnected onto the connector plug contacts 27 of the connector part 26of the electronic module 20; for example two connector plugs areprovided for connection with the voltage supply (for example +12V, −12V)and a bus system (for example a CAN bus system) via a bus control line,over which, for example, the supply voltage is supplied, control signalsare conducted further, and sensor signals are evaluated.

1. Electric drive unit comprising an electric motor (10), an electronicmodule (20), and a transmission (30), wherein a commutator (15), a brushrocker ring (16) arranged on and extending circumferentially around thecommutator (15), and a drive shaft (14) of the electric motor (10), aswell as a carrier body (21) of the electronic module (20) are insertedinto a transmission housing (31), and wherein an electrical connectionbetween the electric motor (10) and the electronic module (20) isachieved in the transmission housing (31) via contact elements (18)which are fixedly arranged on the brush rocker ring (16) and whichreleasably engage into contact points (25) fixedly provided on thecarrier body (21) of the electronic module (20).
 2. Electric drive unitaccording to claim 1, characterized in that the contact elements (18)are embodied as press-in pin contacts, which are pressed and engagedinto the contact points comprising through-contacts in the carrier body(21) of the electronic module (20).
 3. Electric drive unit according toclaim 1, characterized in that the commutator (15), the brush rockerring (16) arranged on the commutator (15), and the drive shaft (14) ofthe electric motor (10) are inserted into the transmission housing (31)via a first opening (32) in a side surface of the transmission housing(31).
 4. Electric drive unit according to claim 3, characterized in thatthe carrier body (21) of the electronic module (20) is inserted into thetransmission housing (31) via another opening at an upper side (36) ofthe transmission housing (31), and in that an upper surface normal axisof the carrier body (21) of the electronic module (20) extendsperpendicularly to the axis of the drive shaft (14) of the electricmotor (10).
 5. Electric drive unit according to claim 3, characterizedin that a second opening (33) is provided in the side surface of thetransmission housing (31), for guiding through a connector part (26)comprising connector plug contacts (27) of the electronic module (20).6. Electric drive unit according to claim 1, characterized in that arotation speed sensor (24) is provided on the carrier body (21) of theelectronic module (20) and is positioned directly below an emitter (19)arranged on the drive shaft (14) of the electric motor (10).
 7. Anelectric drive unit comprising: an electric motor including acommutator, a drive shaft extending from said commutator, a brush rockerring that is arranged on and extends circumferentially around saidcommutator and that carries brushes contacting said commutator, andelectrical contact elements arranged on said brush rocker ring andelectrically connected to said brushes; a transmission engaged with saiddrive shaft; an electronic module including a circuit board, circuitelements arranged on said circuit board, and counterpart contactsprovided on said circuit board and making electrical contact with saidelectrical contact elements arranged on said brush rocker ring; and ahousing in which said motor, said transmission and said electronicmodule are received; wherein said electrical contact elements arecontact pins protruding from said brush rocker ring, said counterpartcontacts are contact sockets provided on said circuit board, and saidcontact pins make electrical contact with said contact sockets by beingrespectively plugged into said contact sockets.
 8. An electric driveunit comprising: an electric motor including a commutator, a drive shaftextending from said commutator, a brush rocker ring that is arranged onand extends circumferentially around said commutator and that carriesbrushes contacting said commutator, and electrical contact elementsarranged on said brush rocker ring and electrically connected to saidbrushes; a transmission engaged with said drive shaft; an electronicmodule including a circuit board, circuit elements arranged on saidcircuit board, and counterpart contacts provided on said circuit boardand making electrical contact with said electrical contact elementsarranged on said brush rocker ring; and a housing in which said motor,said transmission and said electronic module are received; wherein saidhousing has first and second openings, said electric motor is insertedinto said housing through said first opening, and said electronic moduleis inserted into said housing through said second opening.
 9. Anelectric drive unit comprising: an electric motor including acommutator, a drive shaft extending from said commutator, a brush rockerring that is arranged on and extends circumferentially around saidcommutator and that carries brushes contacting said commutator, andelectrical contact elements arranged on said brush rocker ring andelectrically connected to said brushes; a transmission engaged with saiddrive shaft; an electronic module including a circuit board, circuitelements arranged on said circuit board, and counterpart contactsprovided on said circuit board and making electrical contact with saidelectrical contact elements arranged on said brush rocker ring; and ahousing in which said motor, said transmission and said electronicmodule are received; wherein said electric motor including saidcommutator, said drive shaft, said brush rocker ring, said brushes andsaid electrical contact elements forms a first pre-assembled unit thatis inserted into said housing, and said electronic module including saidcircuit board, said circuit elements, and said counterpart contactsforms a second pre-assembled unit that is inserted into said housingseparately from said first pre-assembled unit.
 10. An electric driveunit comprising: a first pre-assembled unit comprising an electric motorincluding a commutator, a drive shaft extending from said commutator, abrush rocker that is arranged on said commutator and that carriesbrushes contacting said commutator, and electrical contact elementsarranged on said brush rocker ring and electrically connected to saidbrushes; a transmission; a second pre-assembled unit comprising anelectronic module including a circuit board, circuit elements arrangedon said circuit board, and counterpart contacts provided on said circuitboard; and a housing in which said transmission, said firstpre-assembled unit and said second pre-assembled unit are assembled sothat said transmission engages with said drive shaft and so that saidelectrical contact elements of said first pre-assembled unitrespectively make electrical contact with said counterpart contacts ofsaid second pre-assembled unit.
 11. The electric drive unit according toclaim 10, wherein one of said electrical contact elements or saidcounterpart contacts comprises a respective contact pin, another of saidelectrical contact elements or said counterpart contacts comprises arespective contact socket, and said contact pin is plugged into saidcontact socket to make said electrical contact therewith when said firstand second pre-assembled units are assembled in said housing.